Ductile shear reinforced bar layout applied to reinforced concrete shear wall structures

ABSTRACT

A ductile shear reinforced bar layout applied to reinforced concrete shear wall structures comprises several vertical reinforced bars, several horizontal reinforced bars, several connecting reinforced bars, a shear reinforced bar, and several reinforced bars, wherein the vertical reinforced bars and the horizontal reinforced bars are intersected to form a plane, the shear reinforced bar structure and the reinforced bars are firmly disposed on the plane, two adjacent planes are connected by the connecting reinforced bars, pouring concrete to the shear reinforced bar connected on the planes and the shear reinforced bar structure being wrapped around by the concrete are to form the shear wall with the RC. Due to irregular vibrations from earthquake, the surface of the wall is cracked along the directions with larger shear forces. Hence, adding the shear reinforced bar structure can avoid cracks and promoting the ability to anti-vibration.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention in question, is a new design of ductile shear reinforcedbar layout and it's application on reinforced concrete shear wallstructures, and in particular to structures containing reinforcedconcrete which improves it's capacity to absorb seismic energy.

2. Description of the Prior Art

At 2:45 in the afternoon on May 12, 2008; the city of Sichuan inMainland China had a strong earthquake registering a magnitude of 8.This caused nearly 70,000 casulties as well as hundreds of thousands ofinjuries. The earthquake caused approximately 216,000 buildings tocollapse, including 6,898 education facilities. The destruction causedby the Wenchuan earthquake's has highlighted the lack of anti-seismicbuildings, and the need for more effective anti-seismic building design.Through the occurrence of the earthquake in Sichuan, two problems werehighlighted: insufficient anti-seismic building design and a lack ofdisaster prevention work. To prevent the level of destructionexperienced after the Sichuan earthquake from happening again, disasterprevention design and the development of seismic resistant technologyneeds be studied.

Most buildings in Mainland China are constructed by reinforced concrete(RC), therefore the shear walls are also made from reinforced concrete(RC). According to post-disaster statistics, the factors which lead tothe damage of houses and school buildings include: pillars that are toosmall, an inferior quality of concrete, a lack of main reinforced bars,insufficient force of the bonding reinforced bars on the pillars, badjoining of main reinforced bars, insufficient RC shear walls, and aninsufficient amount of bonding reinforced bars at the joint parts ofpillars, etc. This demonstrates that the prior design standard is notflexible enough to resist earthquakes. Therefore, the anti-vibration andreinforcement design should aim to improve this non-flexible behavior orto promote seismic capacity.

For low-rise buildings, the RC walls or RC shear walls may greatlyimprove the seismic capacities. When such buildings receive a horizontalload, such as a seismic force, the RC shear wall can withstand theshearing force so as to increase the effect of anti-earthquake. The RCshear wall is generally a square solid component or a rectangular solidmember, which is much rigid in comparison to pillars and columns. Majorseismic forces resisted by the traditional RC shear walls will oftenproduce many giant diagonal cracks after absorbing the seismic tension.In traditional RC shear walls, it is inconvenient to arrange thereinforced bars in any direction other then horizontally or vertically.Since the direction of the largest shear stress of any point in the RCshear wall is dependent on different corresponding positions, the cracksin the RC shear wall cannot be effectively controlled. Afterearthquakes, the cracks in the RC shear wall are mostly diagonal;furthermore, the irregular vibrations from earthquake, the accelerationsand directions of the seismic forces are capricious over time, and ontop of that, the direction of a shear force is not constant. However, aspreviously mentioned, the domestic arrangement of the reinforced barsare mostly horizontal and vertical, which is convenient for applyingin-situ but not for suppressing cracks with various directions.

Since RC shear walls are much stiffer than columns, RC shear walls areable to absorb most horizontal forces whilst columns can only absorb afew horizontal forces. While designing the RC shear wall, the dimensionsof the columns can be decreased in order to save costs. However, inpractice, the RC shear wall not only has the superior seismic capacitybut also saves costs while in construction. The major application of theRC shear wall is an infilling wall to a connecting column that isdisposed between elevators or an independent mount; and the RC shearforce is much thicker than a general concrete wall, sometimes the mostthickness is more than 50 cm. The other application is to dispose the RCshear wall in a column with a larger diameter. Nevertheless, theposition to the RC shear wall may be disposed to a place which may notinterfere the usage.

Damage to RC shear walls are usually brittle damage caused by seismicforces, which it makes obvious that its ductility is worse; owing mainlyto the fact that most seismic forces are absorbed by the RC shear walland delivered to a building above the ground. Thus the arrangement andapplication of the RC shear wall should be designed in detail and atorsional effect to buildings may be avoided in order to match with thecharacteristic of stiffness balance of a building and exert thefunctions of an RC shear wall.

The principles of earthquake-resistance are simple, regularity andsymmetricallity. In many earthquakes, poor structural systems are themain factor. To improve such structural systems, the horizontalsurfaces, vertical surfaces, and the delivering path of seismic forces,etc. should be focused so that stress concentration and torsionaleffect, may be prevented. For old buildings that are weak, the solutionis to add vertical construction materials, such as RC shear walls, toresist horizontal forces. This also raises the lateral stiffness andstrength of a high building, and it is the most economic way toreinforce inferior structural systems.

The stiffness of an RC shear wall is very large for the wall, capable ofhandling most seismic forces. Hence, a detailed design is required toprevent torsional effects which are caused by the uneven distributionsof the horizontal surfaces or vertical surfaces of a building. Besides,in many earthquakes, the cracks damaging an RC shear wall are mostly indiagonal directions and are caused by brittle/shortness forces. On theother hand, reinforced bars of a general RC shear wall are arrangedhorizontally, which is convenient to build but not suitable for shearforces with variable directions; as a result, cracks with differentdirections are hardly controlled. Components of a force along a45-degree direction is the largest for a shear force caused byearthquake, and a reinforced bar net with vertical and horizontalarrangement cannot effectively resist diagonal cracks. When an obliquetension stress is larger than the tensional strength of the concrete,oblique/diagonal cracks happen.

According to an ROC (Republic of China) patent number 585207, thecharacteristics of the prior shear wall are pre-casting shear wall andhas a rectangle member formed by pouring concrete, a plurality ofbonding reinforced bars are vertically disposed in the member, eachbonding reinforced bar has a plurality of vertical reinforced bars, thebonding reinforced bars are intersected. Since vibrations fromearthquake are irregular and the magnitudes and directions of thevibrations are variable with time, the changes of the magnitudes anddirections may cause that the maximum shear stress to change over time.However, because the arrangements of the reinforced bars of the RC shearwall are mostly vertical and horizontal for the convenience of applyingin-situ, it cannot adapt to the dynamic changes required for the maximumshear stress. Therefore the cracks of the RC shear wall are diagonal, asshown in FIG. 1, which illustrates a schematic view of diagonal crackscaused by shear forces after earthquake of a building.

The inventor of the present invention has spent years to developingshear reinforced bar structures and applying them to shear walls madefrom ductile reinforced concrete so as to work out the deficiencies inprior designs.

SUMMARY OF THE INVENTION

The main objective of the present invention is to provide a ductileshear layout to reinforced concrete shear wall structures, which isbetter than the traditional RC shear walls. Because of the newarrangements of the shear reinforced bar, the ductility performance ofRC structures is enhanced and the possibility of causing huge cracksdecreases. Hence, the seismic capacity of the structure increases aswell.

The secondary objective of the present invention is to provide the shearreinforced bar structure applied to the shear wall with ductilereinforced concrete so that different arrangements/figures of the shearreinforced bars are possible for different types of walls.

The shear reinforced bar structure includes many vertical reinforcedbars, a plurality of horizontal reinforced bars, many connectingreinforced bars, a shear reinforced bar, and many reinforced bars,wherein the vertical reinforced bars and the horizontal reinforced barsare intersected to form a plane, then the shear reinforced bar structureand the reinforced bars are firmly disposed on the plane, two adjacentplanes are connected by the connecting reinforced bars; continuouslypouring concrete to the shear reinforced bar connected on the planes andthen the shear reinforced bar structure being wrapped around by theconcrete are to form the shear wall with the content of the reinforcedconcrete (RC). Due to irregular vibrations from earthquake, the surfaceof the wall may be cracked along the directions with larger shear forceswhich causes huge diagonal cracks. As a result, the seismic capacity ofthe structure is suddenly lost, which makes it vital, adding the shearreinforced bar structure which makes it capable of avoiding earliercracks and promoting the flexibility and ability to anti-vibration.

Other features, advantages, and benefits of the invention will becomeapparent in the following description taken in conjunction with thefollowing drawings. It is to be understood that the foregoing generaldescription and following detailed description are exemplary andexplanatory but are not to be restrictive of the invention. Theaccompanying drawings are incorporated in and constitute a part of thisapplication and, together with the description, serve to explain theprinciples of the invention in general terms. Like numerals refer tolike parts throughout the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, spirits, and advantages of the preferred embodiments of thepresent invention will be readily understood by the accompanyingdrawings and detailed descriptions, wherein:

FIG. 1 illustrates a schematic view of diagonal cracks caused by shearforces after earthquake of a building;

FIG. 2 illustrates a schematic plane view of a preferred embodiment of aductile shear reinforced bar layout applied to reinforced concrete shearwall structures of the present invention;

FIG. 3 illustrates a schematic 3-D view of the preferred embodiment ofthe ductile shear reinforced bar layout applied to the reinforcedconcrete shear wall structures of the present invention;

FIG. 4 illustrates a schematic plane view of another preferredembodiment of the ductile shear reinforced bar layout applied to thereinforced concrete shear wall structures of the present invention;

FIG. 5 illustrates a schematic 3-D view of the another preferredembodiment of the ductile shear reinforced bar layout applied to thereinforced concrete shear wall structures of the present invention;

FIG. 6 illustrates a schematic connection view of a welding material ofthe ductile shear reinforced bar layout applied to the reinforcedconcrete shear wall structures of the present invention;

FIG. 7 illustrates a schematic view of an intersection arrangement to along wall of the shear reinforced bar structure of the presentinvention;

FIG. 8 illustrates a schematic view of a variable arrangement to a longwall of the shear reinforced bar structure of the present invention; and

FIG. 9 illustrates a schematic view of the shape of the geometrypolygons of the shear reinforced bar of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following preferred embodiments and figures will be described indetail so as to achieve aforesaid objects.

With reference to FIG. 2, which illustrates a schematic plane view of apreferred embodiment of a ductile shear reinforced bar layout applied toreinforced concrete shear wall structures of the present invention. Thestructure of a shear reinforced bar includes a plurality of verticalreinforced bars 11, a plurality of horizontal reinforced bars 12, aplurality of connecting reinforced bars 3, a shear reinforced bar 13, aplurality of iron wires 14, and a plurality of reinforced bars 131,wherein the vertical reinforced bars 11 and the horizontal reinforcedbars 12 are intersected to form a first plane 1, then the iron wires 14fasten the shear reinforced bar 13 up on the first plane 1. Furthermore,four corners not fastened by the shear reinforced bar 13 are added aplurality of oblique reinforced bar 131 for reinforcement, the shape ofthe shear reinforced bar 13 is a spiral, a plurality of geometrypolygons, a plurality of concentric circles, etc. The material of theshear reinforced bar 13 is a steel bar, a steel cable, a plastic coveredsteel bar, a compound material, etc.

With reference to FIG. 3, which illustrates a schematic 3-D view of thepreferred embodiment of the ductile shear reinforced bar layout appliedto the reinforced concrete shear wall structures of the presentinvention. According to above descriptions, the first plane 1 and asecond plane 2 are connected by the plurality of connecting reinforcedbars 3, then the shear reinforced bar structure is wrapped around byconcrete 4, that is, the shear wall with the content of the reinforcedconcrete (RC) is formed. While earthquake is happening, the directionsof the bigger shear force on an RC shear wall may be cracked due tovariable vibration directions. Therefore many of oblique shear crevicesare caused. However, the problem is being figured out after adding theshear reinforced bar 13.

With reference to FIG. 4, which illustrates a schematic plane view ofanother preferred embodiment of the ductile shear reinforced bar layoutapplied to the reinforced concrete shear wall structures of the presentinvention. The structure of a shear reinforced bar includes a pluralityof vertical reinforced bars 11, a plurality of horizontal reinforcedbars 12 and a shear reinforced bar 13, wherein the vertical reinforcedbars 11 and the horizontal reinforced bars 12 are intersected to form aplane, then the iron wires 14 fasten the shear reinforced bar 13 up onthe plane. Furthermore, four corners not fastened by the shearreinforced bar 13 are added a plurality of oblique reinforced bar 131for reinforcement. For the preferred embodiment, the shape of the shearreinforced bar 13 is formed by a plurality of concentric circles.

With reference to FIG. 5, which illustrates a schematic 3-D view of theanother preferred embodiment of the ductile shear reinforced bar layoutapplied to the reinforced concrete shear wall structures of the presentinvention. The shear reinforced bar can be applied to the shear wallwith the content of reinforced concrete, wherein the vertical reinforcedbar 51 and the horizontal reinforced bar 52 are intersected to form aplane 5, then a shear reinforced bar 53 is fastened by a plurality ofiron wires 54 on the plane 5, four corners not fastened by the shearreinforced bar 53 are added a plurality of oblique reinforced bar 531for reinforcement, then pouring concrete 6 to wrapped around the shearreinforced bar structure is to form the shear wall with the content ofthe ductile reinforced concrete (RC).

With reference to FIG. 6, which illustrates a schematic connection viewof a welding material of the ductile shear reinforced bar layout appliedto the reinforced concrete shear wall structures of the ductilereinforced concrete of the present invention. Wherein the combinationmaterial for the shear reinforced bar 13 and the reinforced bar 131 andthe combination material for the vertical reinforced bar 11 and thehorizontal reinforced bar 12 are a welding material so as to enhance thestrength of combination.

With references to FIG. 7 and FIG. 8, which illustrate a schematic viewof an intersection arrangement to a long wall of the shear reinforcedbar structure of the present invention and a schematic view of avariable arrangement to a long wall of the shear reinforced barstructure of the present invention. As shown in figures, while thepresent invention is applied to a long wall 7, the surface of the longwall 7 can be disposed more than one shear reinforced bar 13, and thearrangement of the shear reinforced bar 13 is a continuous arrangement,furthermore, an intersection arrangement is another example as well. Theshape of the shear reinforced bar is a spiral, a plurality of geometrypolygons, a plurality of concentric circles, etc., and the shearreinforced bar is able to cooperate with the reinforced bars 131 forreinforcement. For the shape of the geometry polygons, please refer toFIG. 9, which illustrates a schematic view of the shape of the geometrypolygons of the shear reinforced bar of the present invention.

The present invention can be in mass produced in a pre-casting factoryin order to shorten the construction period and to promote a efficiencyfor rapidly building up an RC shear wall. This is beneficial topost-disaster rebuilding efforts, which can be completed efficiently, aswell as meeting desired seismic building standards; so that people canobtain basic essential creature comforts as quickly as possible.

Earthquakes shake the ground, twist, rise and fall in ground movement.The movement and size of an earthquake can change at any moment. In theabsence of vibrations, displacement to a structure may occur when cracksare happening, furthermore, if cracks continue to appear, totalcollapsation may be the next step. For an anti-earthquake building, themost common way is to add an RC shear wall to make the swing of thebuilding smaller. The function of RC shear wall is to absorb themajority of vibration forces from earthquakes, so that the RC shear wallcan be the first defense against earthquakes. After the earthquake, thefailure mode of the RC shear wall is mostly represented by obliquecracks. Due to irregular vibrations from the earthquake, the amplitudesand directions of earthquake are variable over time. The changedamplitudes and directions of seismic force of earthquake means that themaximum shear stress also changes over time. Presently, the common wayis to arrange the reinforced bars horizontally and vertically. This wayis more convenient, but it is incapable of adapting to dynamic changesin demand for the maximum shear stress, as a result the cracks of the RCshear wall are diagonal.

Cracks of RC shear walls are mostly diagonal. The angles of the cracksare related to the ratio of the height and width of the RC shear wall,the detail bars disposed inside the RC shear wall and the amplitude ofearthquake. To avoiding such diagonal/oblique cracks, the best way is todispose reinforced bars that are vertical to the cracks. Then, circularbars are added into the RC shear wall. The circular bar is a spiral, aplurality of geometry polygons, a plurality of concentric circles, etc.in order to control the possibility of causing cracks.

Compare to prior designs, the ductile shear reinforced bar layoutapplied to reinforced concrete shear wall structures provided by thepresent invention has the advantages listed below:

-   1. The arrangement of the shear reinforced bar of the present    invention improves the ability of anti-vibration and prevents the    huge diagonal cracks, the seismic capacity of the structure also    improves.-   2. Different arrangements/figures of the shear reinforced bar can be    adopted to different types of walls.-   3. The present invention can be reduced in mass-production in a    pre-casting factory in order to raise/increase the working    efficiency.

Although the invention has been disclosed and illustrated with referenceto particular embodiments, the principles involved are susceptible foruse in numerous other embodiments that will be apparent to personsskilled in the art. This invention is, therefore, to be limited only asindicated by the scope of the appended claims

1. A ductile shear reinforced bar layout applied to reinforced concreteshear wall structures comprising at least one vertical reinforced bar,at least one horizontal reinforced bar and at least one connectingreinforced bar, the vertical reinforced bar and the horizontalreinforced bar being intersected to form a plane, then two adjacentplanes being connected by the connecting reinforced bar, characterizedin that: pouring concrete to a shear reinforced bar e connected on theplanes and then the shear reinforced bar structure being wrapped aroundby the concrete are to form the shear wall with the content of thereinforced concrete (RC).
 2. The ductile shear reinforced bar layoutapplied to the reinforced concrete shear wall structures according toclaim 1, wherein four corners not fastened by the shear reinforced barare added a plurality of oblique reinforced bar.
 3. The ductile shearreinforced bar layout applied to the reinforced concrete shear wallstructures according to claim 1, wherein the shape of the shearreinforced bar is selected from the group comprising a spiral, aplurality of geometry polygons and a plurality of concentric circles. 4.The ductile shear reinforced bar layout applied to the reinforcedconcrete shear wall structures according to claim 1, wherein thematerial of the shear reinforced bar is selected from the groupcomprising a steel bar, a steel cable, a plastic covered steel bar, anda compound material.
 5. The ductile shear reinforced bar layout appliedto the reinforced concrete shear wall structures according to claim 1,wherein at least one iron wire fastens the shear reinforced bar up. 6.The ductile shear reinforced bar layout applied to the reinforcedconcrete shear wall structures according to claim 1, wherein at leastone welding material fastens the shear reinforced bar up.
 7. The ductileshear reinforced bar layout applied to the reinforced concrete shearwall structures according to claim 1, wherein the arrangement of theshear reinforced bar is selected from the group comprising acontinuation arrangement and an intersection arrangement.
 8. A ductileshear reinforced bar layout applied to reinforced concrete shear wallstructures comprising at least one vertical reinforced bar and at leastone horizontal reinforced bar, the vertical reinforced bar and thehorizontal reinforced bar being intersected to form a plane,characterized in that: pouring concrete to a shear reinforced bar econnected on the plane and then the shear reinforced bar structure beingwrapped around by the concrete are to form the shear wall with thecontent of the reinforced concrete (RC).
 9. The ductile shear reinforcedbar layout applied to the reinforced concrete shear wall structuresaccording to claim 8, wherein four corners not fastened by the shearreinforced bar are added a plurality of oblique reinforced bar.
 10. Theductile shear reinforced bar layout applied to the reinforced concreteshear wall structures according to claim 8, wherein the shape of theshear reinforced bar is selected from the group comprising a spiral, aplurality of geometry polygons and a plurality of concentric circles.11. The ductile shear reinforced bar layout applied to the reinforcedconcrete shear wall structures according to claim 8, wherein thematerial of the shear reinforced bar is selected from the groupcomprising a steel bar, a steel cable, a plastic covered steel bar, anda compound material.
 12. The ductile shear reinforced bar layout appliedto the reinforced concrete shear wall structures according to claim 8,wherein at least one iron wire fastens the shear reinforced bar up. 13.The ductile shear reinforced bar layout applied to the reinforcedconcrete shear wall structures according to claim 8, wherein at leastone welding material fastens the shear reinforced bar up.
 14. Theductile shear reinforced bar layout applied to the reinforced concreteshear wall structures according to claim 8, wherein the arrangement ofthe shear reinforced bar is selected from the group comprising acontinuation arrangement and an intersection arrangement.